Railway traffic controlling apparatus



june 2, 1936. R MccANN RAILWAY TRAFFIC CONTROLLING APPARATUS IN VENTORF M a E m k 4? m Q KW MN IL Am @Q Q Mi ATTORNEY.

m ml N L hl 15H v $3 wk 9w 6 Q E N 9% M Ll IF m I F m ml mi w aw. m. f Q gm Patented June 2, 1936 UNETED STATES PATENT OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Application April 22, 1931, Serial No. 532,026 Renewed March 29, 1932 5 Claims.

My invention relates to railway traflic controlling apparatus, and particularly to apparatus of the type involving track circuits. One feature of my invention is the provision, in apparatus of this character, of means for preventing improper operation in the event that when a light engine or a gasoline car passesfrom one section into another the track relay for the first section closes before the track relay for the second section opens.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention.

Referring to the drawing, the reference characters and I designate the rails of a stretch of railway track along which traffic moves in both directions. These rails are divided by insulated joints 2 to form blocks CD, D E, etc., and each block is further divided by insulated joints 2 to form at least two track sections. Each section is provided with a track circuit comprising a battery 3 and a track relay T. Traffic moving toward the right is governed by signals SC, SD, and SE, etc., each of which, as here shown, is in the form of a light signal having the usual proceed, caution and stop lamps G, Y and R, respectively.

Associated with each signal SC and SD is a polarized home relay H, a repeater relay R, and a stick relay X, and these relays, in the form of apparatus shown herein, are controlled in accordance with what is known as Absolute permissive block signaling.

Each relay R is provided with a circuit which passes from terminal B of a suitable source of current, through front contact l6 of the associated relay H, and the winding of relay R to terminal O of the same source of current. It follows that each relay R is energized when the associated relay H is energized in either direction, and is deenergized when the associated relay H is deenergized. Each relay R has both slow pick-' up and slow releasing characteristics.

Relay HC is provided with a circuit which passes from terminal B, through front contact 6 of relay HD, front point of contact of relay RD, front, contact 8 of track relay TDI, front contact 9 of track relay TC, the winding of relay HC, and the front point of contact 0 of relay RD, to terminal 0. When this circuit is closed, relay HC is energizedby current of normal po-' larity, so that its polar contact 2| is swung to the left. Whenrelays HD and RD are both deenergized and relay XD is energized, an auxiliary circuit for relay HC is closed, which circuit is from terminal B, through front contact ll of relay XI), back point of contact H] of relay RD, winding of relay HC, contacts 9 and 8 of 5 track relays TC and TDI, and back point of contact of relay RD, to terminal 0. When this circuit is closed, current of reverse polarity is supplied to relay HC, so that the polar contact 2| of this relay is swung to the right. 10

Relay HD is controlled by contacts 9 and 8 of track relays TD and TEI, and by pole-changing contacts i2 and I5 of home relay HE. The control is such that when block D-E is unoccupied, relay I-ID will be energized in the normal or the 15 reverse direction, according as relay HE is energized or deenergized.

Relay XD is provided with a pick-up circuit which passes from terminal B, through back con tact I! of track relay TD, front point of contact 20 I8 of relay RD, and the winding of relay XD, to terminal 0. This relay is also provided with a stick circuit which passes from terminal B, through back point of contact 8 of relay RD, front contact IQ of relay XD, and the winding of relay XD, to terminal 0. The circuits for the control of stick relay XC are similar to those for the control of relay XD.

The lamps of signal SD are controlled in the usual manner by the contacts of relays HD and RD. That is to say, when relay HD is energized in the normal direction, lamp G will be lighted by virtue of a circuit which includes the front point of contact 20 of relay RD and contact 2| of relay HD in the normal position. When relay HD is energized in the reverse direction, lamp Y will be lighted by virtue of a circuit which includes the front contact 20 of relay RD and contact 2| in the reverse position. When relay RD is deenergized, lamp R will be lighted by virtue of a circuit which includes the back point of contact 20. The circuits for the signal SC are similar to those for signal SD.

The operation of the apparatus'is as follows: When a train moving toward the right enters section C4, it will open track relay TC, therea by opening the circuit for relay HC, and this,

it will open track relay TD, thereby opening relays HD and RD and closing relay EC). When the rear end of the train has passed entirely out of the section 4D, relay I-IC will become energized in the reverse direction, thereby causing the caution lamp Y of signal SC to become lighted. When the train passes into section 5E, it will cause no change in the condition of the apparatus, except to deenergize relay TEI. When the train passes point E, the caution lamp Y of signal SD will become lighted, and the proceed lamp of signal SC will become lighted.

I will now assume that while a short vehicle, such as a light engine or gasoline electric car, is passing the point D, track relay TDI closes before track relay TD opens. This will permit relay 1-10 to be momentarily energized in the normal direction, and if relay RC were a quick pick-up relay, the proceed lamp G of signal SC would be momentarily lighted. Inasmuch as this relay RC is characterized by requiring a time interval to close its front contacts after the relay becomes energized, this relay will not close during the brief interval of time between the closing of track relay TDI and the opening of track relay TD, and so the proceed lamp G of signal SC will not be momentarily lighted. That is to say, lamp R of this signal will remain lighted until relay I-IC becomes energized in the reverse direction to cause lamp Y to become lighted.

Furthermore, when a short vehicle passes point 5, relay TD may close before relay TEI opens, and this will allow relay HD to be momentarily energized. If relay RD were a quick pick-up relay, it would open its back contacts during this brief energization of relay I-ID, and would thereby open the stick circuit for relay XD, with the result that the auxiliary circuit for relay HC would be opened and would remain open after relay TEI opens. This would extinguish the caution lamp Y of signal SC, and would light thestop lamp R of this signal. Inasmuch as relay RD has a slow pick-up characteristic, it will not open its back contacts during the brief energization of relay HD referred to above, and so the stick circuit for relay XD will not be opened.

Owing to the slow-releasing characteristic of each relay RC and RD, the associated signal is prevented from momentarily giving a stop indication during the reversal of the polar contact 2| of the associated relay H, but this is not a novel feature of the present invention.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a block of railway track divided to form two track sections, a track circuit including a track relay for each section, means including a home relay for governing trafiic in one direction through said block, a circuit for said home relay including front contacts of both of said track relays, a repeater relay controlled by a front contact of said home relay and having slow pick-up and slow releasing characteristics, a stick relay; control means for said stick relay delaying a change in the condition of the relay during the pickup time of said repeater relay to prevent such change during a brief simultaneous energization of both said track relays and comprising a pick-up circuit for said stick relay including a back contact of the track relay first opened by a train moving in said one direction entering said block as well as a front contact of said repeater relay, and a stick circuit for said stick relay including a back contact of said repeater relay; and means controlled by said stick relay for governing traffic moving in said one direction approaching said block.

2. In combination, a stretch of railway track divided to form a rear and a forward block, track circuits including track relays for said blocks, a home relay for the forward block controlled by the track relays for such block, a first repeater relay controlled by said home relay, a stick relay for said forward block, means for energizing said stick relay when a vehicle enters the forward block from the rear block and for keeping it energized as long as the train occupies the forward block, a second home relay for the rear block, means operating when the rear block is unoccupied to energize said second home relay in norma1 direction if said first repeater relay is closed and in reverse direction when said first repeater relay is open and said stick relay is closed, a second repeater relay for said rear block controlled by said second home relay and having slow pick-up and slow releasing characteristics, proceed and caution indication cir-' cuits for said rear block controlled by a front contact of said second repeater relay, and a stop indication circuit for said rear block controlled by a back contact of said second repeater relay, whereby the slow pick-up characteristic of said second repeater relay retains said stop indicaticn circuit closed after the energization of said second home relay upon the passage of a train from said rear block into said forward block until after said first home relay has released.

3. In an absolute permissive block signaling system for railroads, the combination with two successive sections of track, of a track relay for each section, a line relay associated with an intermediate signal and controlled by both of said track relays, a repeater relay having a winding and front and back contacts operated by said winding which contacts are slow to close and open respectively when the winding becomes energized, a circuit including said winding and a front contact of said line relay, and a directional stick relay having a pickup circuit including a front contact of said repeater relay and a stick circuit including a back contact of said repeater relay whereby said directional relay is prevented from becoming energized, or if energized, is prevented from becoming released, in the event that one of said track relays picks up before the other releases, due to the movement of a train from one of said track circuits to the other, and energizes said line relay for a period longer than the usualpickup time of a quick acting relay.

4. In an absolute permissive block signaling system for railroads, the combination with the track relays of two adjacent track sections of said system, the usual line relay controlled by front contacts of said track relays, and the usual directional stick relay, a repeater relay having a winding and front and back contacts operated by said winding which contacts are slow to close and open respectively when the winding becomes energized, a circuit including said winding and a front contact of said line relay, a pick-up and 75 a stick circuit for said directional stick relay, each including a back contact of one of said track relays, said pickup circuit also including the front contact of the repeater relay, and a second stick circuit for said directional relay including the back contact of the repeater relay, whereby a change in the condition of said directional relay is delayed after an energization of said line relay until the expiration of the slow pickup period of said repeater relay.

5. In a railway signaling system, in combination with two consecutive block sections each having track circuits provided with track relays, a line relay for the advance section controlled by the track relays of such section; a line relay for the rear section controlled by the track relays of such section and by the line relay for the advance section; a repeater relay having a winding included in a circuit with a front contact of the line relay for the rear section and contacts which are slow to operate when the winding becomes energized, and a signal for the rear section controlled by contacts of said repeater relay, whereby a change in the indication of said signal is delayed during the slow pickup period of said repeater relay in the event the line relay for the rear section picks up before the line relay for the advance section releases due to the movement of a train from the rear section to the advance section.

RONALD A. MCCANN. 

